The redox balance of healthy Brazilian adults is associated with GPX1 Pro198Leu and -602A/G polymorphisms, selenium status, and anthropometric and lifestyle parameters

Antioxidant effects of Se-glutathione peroxidase in alcoholic liver disease

Oxidative damage induced by ethanol and its metabolites is one of the factors that fuels the development of alcoholic liver disease (ALD). Selenium (Se) is an effective cofactor for glutathione peroxidase (GPx), and has antioxidant effects that improve ALD. In patients with ALD, ethanol-induced oxidative damage inhibits the synthesis of related Se-containing proteins such as: selenoprotein P (Sepp1), albumin (ALB), and GPx in the liver, thus decreasing the overall Se level in patients. Both Se deficiency and excess can affect the expression of GPx, resulting in damage to the antioxidant defense system. This damage enhances oxidative stress by increasing the levels of reactive oxygen species (ROS) in the body, which aggravates the inflammatory response, lipid metabolism disorder, and lipid peroxidation and worsens ALD symptoms. A cascade of oxidative damages caused by ALD will deplete selenium deposition in the body, stimulate the expression of Gpx1, Sepp1, and Gpx4, and thus mobilize systemic selenoproteins, which can restore GPx activity in the hepatocytes of ALD patients, reduce the levels of reactive oxygen species and alleviate oxidative stress, the inflammatory response, lipid metabolism disorder, and lipid peroxidation, thus helping to mitigate ALD. This review provides a reference for future ALD studies that evaluate the regulation of Se levels and contributes to studies on the potential pathological mechanisms of Se imbalance in ALD.

Intersection between Obesity, Dietary Selenium, and Statin Therapy in Brazil

Obesity is among the most alarming health concerns, impacting public health and causing a socioeconomic challenge, especially in developing countries like Brazil, where approximately one quart of the population presents obesity. As an established risk factor for numerous comorbidities with a multifactorial etiology, obesity is a consequence of energy-dense overfeeding, however with significant undernourishment, leading to excessive adipose tissue accumulation and dysfunction, dyslipidemia, and micronutrient deficiencies. About 60% of patients with obesity take statins, a cholesterol-lowering medication, to curb dyslipidemia, with ~10% of these patients presenting various myopathies as side effects. Statins act upon the rate-limiting enzyme of cholesterol biosynthesis in the liver, which is a pathway providing intermediates to the synthesis of selenoproteins, i.e., enzymes containing the micronutrient selenium. Statins have been postulated to negatively impact selenoprotein synthesis, particularly in conditions of selenium deficiency, and potentially implicated in the myopathies occurring as side effects of statins. The Brazilian population is prone to selenium deficiency, hence could be considered more susceptible to statin side effects. This review examines the specific consequences to the Brazilian population of the harmful intersection between obesity development and concomitant micronutrient deficiencies, particularly selenium, combined with statin treatment in the context of nutrition in Brazil.

Dietary Selenium Intake and Type-2 Diabetes: A Cross-Sectional Population-Based Study on CUME Project

Background and Aim: Previous studies have suggested that the specific association between selenium (Se) and diabetes remains unclear. This study aimed to investigate the association between dietary Se and type-2 diabetes (T2D) in the Brazilian cohort [Cohort of Universities of Minas Gerais (CUME)]. Methods and Results: This cross-sectional study was conducted with a large sample comprising 4,106 participants of the CUME project, a concurrent open cohort restricted to a highly educated population group, composed of graduates of federal institutions of higher education located in the State of Minas Gerais, Brazil. Data on socioeconomic and dietary characteristics, as well as anthropometric measures, were collected from each subject for analysis. The sample was classified into energy-adjusted tertiles of dietary Se intake (μg/day). Differences in the continuous data were evaluated by the Kruskal-Wallis H-test (abnormal data), and the χ²-test assessed differences in qualitative data. As there was no relationship between T2D and Se intake in the bivariate analysis, multivariate analysis was not performed. The prevalence of T2D in the studied population was 2.8%. The mean age was 36 years. Regarding gender, 1,209 are males and 2,807 are females. Among females, the mean Se intake was 165.12 μg/day and the mean intake was 157.4 μg/day. Among males, it was 168.4 μg/day. Significant differences were observed across all Se intake tertiles in terms of age, gender, activity level, alcohol intake, energy intake, sugar, carbohydrates, lipids, fiber, and energy-adjusted meat intake. However, no significant differences were observed across all Se intake tertiles in terms of BMI, smoking status, and T2D. The results indicated that there was no significant association between dietary Se intake and the prevalence of T2D. Conclusion: Dietary Se intake was not associated with the prevalence of T2D, despite the high intake of this micronutrient in the sample. These results contradict studies that identified the association between Se intake and T2D, with values of Se intake much lower than those observed in this study. Thus, this relationship seems to remain controversial.

The influence of nutrigenetics on biomarkers of selenium nutritional status

Selenium (Se) is an essential micronutrient for human biology that executes its functions as the amino acid selenocysteine via selenoproteins, which have important functions in, for example, antioxidation, immunomodulation, thyroid metabolism, and human fertility. Se nutritional status is assessed using the quantification of blood Se biomarkers, which are influenced by several factors, including diet, age, gender, smoking status, alcohol consumption, health condition, and the genetic characteristics of individuals. Nutrigenetic studies have identified single nucleotide polymorphisms in selenoproteins that might clarify the high variability in values reported for biomarkers of Se nutritional status in different populations, and the response of these biomarkers to Se supplementation with either organic or inorganic forms of Se. This review aims to (1) define the basic aspects of Se biology, (2) describe the current most commonly used biomarkers of Se nutritional status, and (3) provide a summary of associations between functional single nucleotide polymorphisms in selenoproteins and biomarkers of Se status in healthy populations.